HVAC systems can be used to regulate the environment within an enclosed space. Typically, an air blower is used to pull air from the enclosed space into the HVAC system through ducts and push the air back into the enclosed space through additional ducts after conditioning the air (e.g., heating, cooling or dehumidifying the air). Various types of HVAC systems, such as roof top units, may be used to provide conditioned air for enclosed spaces.
At a particular site, multiple HVAC units may be used to provide conditioned air for an enclosed space. For example, one building may employ multiple rooftop units to provide conditioned air. Often each of the HVAC units may be coupled to a communications network that allows, for example, the downloading of updates, communicating between other HVAC units, verifying of commission, verifying of service, remote monitoring or remote managing. For reliable communications, each HVAC unit needs a network address that comports with the communications network that is being used. The network address allows directed communication to the controller of each HVAC unit. Often, to insure proper communication, each HVAC controller may need to be manually programmed with a network address that complies with the communications network that is being used.
In addition to needing a network address, the HVAC controllers may also need battery back-up to maintain operation when power is lost. Without battery back-up or another type of back-up power source, the HVAC controllers may be unable to maintain the current date and current time following a system reset. As such, the HVAC controllers may not be able to determine the current date and time at start-up of each HVAC unit.